Last Saturday, our FoodCie member Koen had the spontaneous idea to go out for dinner with the FoodCie. So we did! The choice of restaurant was determined very quickly. The burgers from ‘De Kater’ were calling for us!

We arrived without a reservation on a busy Saturday night, so we obviously had to wait a little bit at the bar. Our fellow beast and bartender at de Kater, Sven, made us some nice drinks and cocktails and soon a table became available!

Koen and Ricky ordered the chicken burger, me (Eva) and Nacari ordered the bacon and cheese burger, Jasmijn had a beef skewer and Kevin was just there for the fun (and alcohol)!

It all tasted very nice, and the amount that was supplied was sufficient.

Our meat was cooked medium (the way we wanted it) and seasoned nicely. Koen got a cute salad on the side instead of fries. The chicken burger had a different seasoning than last time, and Koen thought that the previous seasoning was a bit better!

Unfortunately we had to go to a festival after this dinner, so we did not get a dessert.

The final score for this restaurant:

Service: 8+

The service was great, everything was arranged quickly and efficiently.

Atmosphere: 7

We are giving the general atmosphere of the restaurant a 7, this is because of the old fashioned style that they went for. Some of us liked it very much, some of us did not.

Food: 9

The burgers are wonderful, just like the other dishes. The price-quality ratio is great, good food for a small price.

When a girl tells people she just started lifting, they often think that she will wake up as a Hulk the next day. They think that lifting makes women look bulky, so they shouldn’t train like men. Another thing you often hear, is that women can never get as big as men, but is that true? Do women naturally have less muscular potential than men? Or can we finally acknowledge the fact that women should train heavy too and that a lot of girls are not living up to their potential by lifting 2 kg pink dumbbells?

The natural muscular potential of women.

Popular opinion is that men have more muscular potential than women and thus can gain more muscle. However, some research indicates that women naturally have roughly the same muscle building potential. A prospective intervention study examined the influences of gender on muscle size responses to strength training. The results were that women can gain the same percentage of muscle mass compared to men during strength training [1].

Studies on protein synthesis came also to the same conclusion. Women have similar muscle protein synthesis rates and thus seem to build the same amount of muscle protein after training compared to men [2]. This is however the conclusion of only a few studies, so more research is definitely needed to be 100% clear that women do naturally have the same muscle building potential. However, this is difficult because these studies take a long time and need to be well-controlled.

When women start training they do have a different body composition. Most of the times, women have less muscle mass and more fat mass compared to men. Women have +/- 12% essential body fat compared to just +/- 3% fat in men [3]. Essential body fat is all the fat which we can not lose without it negatively affecting our physiological functions. It surrounds our organs and nerve tissues. Men and women do have a different starting point when it comes to muscle mass, but they seem to be gaining muscle mass at the same rate. Keep in mind that for the rest of this article I always compare men with a starting point to women with the same starting point, so a same body composition.

How about testosterone?

Testosterone is the most important male sex hormone. Women however do also produce testosterone, even though they have 15 times less active testosterone than men, under normal circumstances [4]. Besides the known functions of testosterone in our body, like development of primary/secondary sexual characteristics and production of sperm, it also plays a positive role in muscle building. Testosterone is an anabolic hormone, which means that it stimulates muscle protein synthesis and thus muscle growth.

Is it then true, because women have less testosterone they also have less potential to build muscle mass? No, this is probably not the case. The testosterone functions are different in men and women. What comes next might be a bit of a complicated story with terms you never heard about, but do not worry about that and try to see the big picture in why having less testosterone as a woman is not that bad at all.

It seems that testosterone is not needed for muscle development in women because growth factors like IGF-1 and growth hormone take over the anabolic role that testosterone plays in men [5]. This has been found in an animal study done with mice, so more studies are necessary to test if this is the case in humans too. However since women can gain muscle with lower testosterone levels, it can be safely assumed that other hormones besides testosterone are involved in this muscle building process.

Women have just as much IGF-1 and produce +/- 3 times as much growth hormone as men [6]. This study shows that despite the fact that women have lower testosterone levels than men, they do have higher growth hormone levels. It could be possible that in women growth hormone partly takes over the role of testosterone. This explains why having less testosterone does probably not limit how much muscle women can build. People think that testosterone is the most important hormone, but there are more hormones that play a role in muscle growth.

The other (sex)hormones combined with the advantages/disadvantages women have.

Estrogen

Where testosterone is the most important male sex hormone, estrogen is the most important female sex hormone. Estrogen is commonly seen as the hormone that makes you fat and frail. However, its positive effects should not be disregarded. Some of these positive physiological effects are:

It is anti-catabolic, which means that it prevents muscle loss [7].

It aids in muscle repair [8].

It is good for connective tissue (bones, ligaments etc.).

The bad reputation of estrogen is based on nothing more than the assumption that if testosterone is anabolic, estrogen must be catabolic. There is a lot of ongoing research and there are indications that it plays a role in muscle growth and the well-being of skeletal muscle. However, more research is needed in the future.

Progesterone

One big disadvantage for a lot of women these days is the use of the anti-contraceptive pill. This holds especially true for the ones containing a lot of progesterone. They do have a negative effect on muscle growth compared to not using an anti-contraceptive pill, because progesterone competes with testosterone for the androgen receptor. Basically, this comes down to less active testosterone when you take in an anti-contraceptive pill with a lot of progesterone [9]. How much of a negative effect occurs is hard to tell, because it is very difficult to study.

Here is a practical tip which you can use to take advantage of the benefit we have being a woman. Hopefully this and more research in the future about some other topics relating the effects of hormones on muscle growth will help you get the most out of your training sessions!

We can use a higher rep range.

There are two types of muscle fibres: Type I&II. Type I muscle fibers are known as slow-twitch muscle fibers, which makes them able to contract for a long period of time and more resistant to fatigue. Being able to contract for a long period of time could mean that women can benefit from a higher rep range. This could mean that for women to grow to their full potential, more reps per set need to be done to benefit from the type I fibres which are more resistant to fatigue and can contract longer. One study came to the conclusion that during exercise in women, a potential conversion to type I muscle fibers or no conversion at all takes place [10]. This study looked at the muscle fibre adaptations during execution of a knee-extension exercise in both young men and women. They found a significant increase in percentage of type I fibres in young women. The study has its limitations: if the muscle fibres had been splitted into type Ia, IIa, IIb etcetera, no significant result would have been found. This also is anecdotal evidence and more research needs to be done.

Conclusion, do women naturally have less muscle building potential than men?

There is some research which indicates that women can gain the same percentage of muscle mass compared to men during strength training [1,2]. However more research is needed.

Why you see more men with a significant amount of muscle mass compared to women and why women aren’t 100% living up to their potential can be contributed to a lot of factors:

Mostly social-cultural. There are not as many women compared to men training with weights. If they do train, some of them just do not want to build as much mass as possible. Everyone has their own goal and idea of how they want to look. That is okay, as long as you do what makes you happy and never have someone telling you what you shouldn’t or can’t achieve.

If women go to the gym, they spend countless hours on the treadmill or playing around with pink dumbbells, that is for sure not 100% optimal if you want to build as much muscle mass as possible.

Oral-contraceptives, which have a negative effect on muscle growth. Part of the anabolic role of testosterone will be taken over by other hormones in women, so testosterone production probably does not limit how much muscle women can build.

More information about this topic for sure will come available in the future as more and more studies are being done on this interesting topic. When that time comes we will update this article and bring you the latest conclusions.

One take home message for all the women out there busting their ass off (or on) in the gym: you probably are not less capable of putting on muscle mass than men, and the only limitations you have are the ones you put on yourself!

References.

[1] Roth, SM (2001). Muscle size responses to strength training in young and older men and women. Journal of the American Geriatrics Society, 49(11), 1428-33.

[2] O’Hagan, FT (1995). Response to resistance training in young women and men. International journal of sports medicine, 16(5), 314-21.

In case you don’t want to eat some breakfast during the summer but want something refreshing and filling, smoothies are delicious in the morning and if done properly healthy AF. Here are some combinations of some breakfast smoothies.

Serve them cold!

Amount per shake are to your tasting. All combinations are possible, just experiment.

Summer is basically here (and God knows for how long) and if there’s one thing I love baking in this season it’s delicious pies. It’s a perfect finish to a nice barbecue, especially with a side of ice cream.

This my personal favorite apple pie recipe. Although I like the Dutch version of the apple pie very much (which is excellent in its own right) I have a slight preference towards the American way of doing things when it comes to this pomaceous desert. The main difference in this case is that the pie crust in the American way is flakier and less sweet. Just for clarification, I’m not completely sure this recipe is up to par with the traditional standards they us back in Murica, but this is simply a pie based on the same concepts they use on the other side of the pond. It’s easy, has few ingredients and you can play with it as you like. The only downside is that it usually takes about a whole day to make, so be sure to make it in advance!

Ingredients:

Basically you make two dough balls. One for the base and the other one to cover up with.

Add the flour and salt together and mix. Then add the butter by cutting off small cubes and dumping it into the dough. Mix this with a fork. Not with an electric mixer! You don’t want the butter to spread evenly – the little clumps will make for pockets of air in the dough when it’s baking, making your dough flakey (luchtig) instead of hard and dense. Now you add the cold water. Make sure it’s cold as you don’t want the butter to melt. With each spoonful stir the mixture until your dough starts to stick together a little. It’s okay if it’s still in clumps! What’s important is that it can be formed into a ball when you knead the though – and adding too much water makes it sticky. When finished wrap plastic foil around your dough and refrigerate for about 5 hours-overnight.

Afterwards take the first dough out and roll it out into a nice thin bottom. Place this over pan, make sure you push it into the edges and refrigerate this for about half an hour. Then put apples (and cinnamon and sugar and raisins, if necessary) into the bottom. Roll out the second dough ball and put over the filling, making sure to pinch the sides of your two doughs (top and bottom) together. Now slice a couple of holes on the top of your pie and it’s ready for the oven! Put it into a 1800c preheated oven and it should be ready in about 45 minutes.
Wait an hour to cool and enjoy!

BCAA’s are thought to put you in an anabolic state. Some people claim that you should use them before training when you are in a fasted state to prevent muscle loss. Is this true and should we all run to the nearest shop to spare our gains? Or is it just a smart marketing strategy from producing companies?

What are BCAA’s?

BCAA’s are branched-chain amino acids. These amino acids are branched (in Dutch vertakt), which in comparison to other amino acids makes it easier for enzymes to digest. Amino acids are the building blocks of proteins. When we consume protein our body uses specific enzymes which breaks these down into smaller units, the amino acids. There are 20 amino acids which can be converted into one another. At least, that’s true for the non-essential ones. The essential amino acids need to be present in our food because the body can’t synthesize them itself. There are 8 essential amino acids: Lysine, Tryptophan, Phenylalanine, Leucine, Isoleucine, Threonine, Methionine and Valine.

The three BCAA’s are Leucine, Isoleucine and Valine. During intensive activity, muscles will convert these quickly into energy. BCAA’s are supplemented just before or during training. The reason for supplementation is to stop muscle breakdown, recover quicker and in the long run build more muscle mass and strength. [1]

Are BCAA’s useful?

Many studies have been done on BCAA’s. A lot of people claim that you should take them before training fasted or during training. Some studies do find an effect of supplementation, whilst others don’t. There are many promising abstracts, but they are almost always hampered by lack of dietary control and/or a low protein intake. Making real conclusions based on these studies is hard.

A randomized, double-blind, placebo controlled study concluded the opposite. Participants received a BCAA supplement or a placebo. Before and after the damaging exercise (100 drop-jumps) they measured different muscle damage variables. They concluded that BCAA administered before and following damaging resistance exercise reduces markers of muscle damage and accelerates recovery in resistance-trained males. This might be due to greater bioavailability of substrate to improve protein synthesis. [3]

Research which shows a net anabolic effect of BCAA supplementation before, during or after training is often used to sell these powders [4]. Supplementing BCAA’s would eventually increase build-up of muscle. No evidence supports that ingestion of BCAA supplements is more effective than consuming a proper amount of food (protein) with respect to building muscle. In fact, there’s research to the contrary: food, and whey protein specifically, may be even more effective than a BCAA drink [5]. This is why you can consume a whey shake before training to get into a net anabolic state. It’s cheaper than BCAA powders, comes in many delicious flavours and is more effective.

What are the costs of BCAA’s?

BCAA’s can be bought in shops and online. The prices differ per brand and they sell both powders as tablets. For example, BCAA’s from Body & Fitshop will cost you €14,90 for 500 grams. The recommended daily serving is 20 grams before or during training, so a package lasts for about 25 days. Thus, quite expensive.

The amino acids shown in the picture above (Amino X from BSN) are even more expensive. You pay €19,90 for 435 grams. The daily serving is 29 grams, so you would pay €1,33 on a daily. Are these any better than Body & Fitshop own label? They both contain the three amino acids L-leucine, L-isoleucine and L-valine but probably in a bit different ratio. The Amino X also contains L-alanine, Taurine and L-arginine and vit D3 + vit B6. Will this add any effect to the product itself? Not sure, but you will just pay for something extra next to the BCAA’s you actually want to buy.

Selling BCAA’s on the market is a smart marketing strategy, because you basically pay for only three amino acids with a bit of a nice flavour added to it. Companies make good use of this by slogans as: ‘Amino X BSN, next level technology!’ or ‘BCAA Sensation V2 only contains the perfect ratio amino acids’. Yeah right if this would all be true, would just not one product with everything be enough? Companies try to come up with new things to make us consumers think that we just have to buy the new product. Smart marketing strategy it is!

Conclusion, BCAA’s: a smart marketing strategy?

Concluded can be so far:

The studies find a mixed effect of supplementation, but if they do find an effect are lacking in many aspects.

They are a smart marketing strategy.

They are expensive.

You can get your BCAA’s from food instead which is cheaper and more satisfying.In general, there are studies that seem to show promising effects of supplementation. These however are hampered when taking a closer look. A whey shake just before training has shown to be even more effective in provoking a net anabolic response.

If you think that you need to take a serving of BCAA’s before training fasted, first ask yourself the following. Is training fasted going to be any better in losing fat than having a meal and smash the hell out of your cardio session? An article about fasted morning cardio might follow, but at the end of the day it still comes down to being in a negative energy balance. If you enjoy doing cardio first thing in the morning go ahead, but don’t get deceived by this BCAA marketing strategy, drink a whey shake and save yourself money!

We probably all know the struggle of cutting. Sometimes it is difficult to lose fat, even though you are in a caloric deficit. Cardio is a helpful tool to cut down on body fat. Some speculation exists about the cardio intensity that would be optimal to burn fat. Is it better to do cardio with a low intensity for a long time, or a high intensity for a short time?

Energy systems in the body
Before explaining what the ideal form of cardio is for burning fat, you should have a basic understanding of metabolism in the human body.

The body needs energy for a lot of different processes: basic functions to stay alive, repair and growth of tissue, and physical activity[1]. In this situation we are mainly interested in the latter one. The body gets its energy from the conversion of ATP to ADP (I am sure you know what that is by now). To create ATP, several forms of fuel are used, such as carbohydrates (sugars), fats (fatty acids), and ketone bodies (which are only formed and used when being in a fasted state). These fuels are present in blood and stored in the body. After a meal, food is digested and taken up in the blood via the intestines. However, only small amounts of nutrients are present in the blood, because the blood has a strict range of concentrations of nutrients and other compounds. If these concentrations would be much lower or higher, the body cannot function properly. For example, in total only a few grams of sugar are present in the blood, providing the body with about 20-30 kilo calories (kcal). When you cycle for 2 minutes, all of this sugar will be used up. Therefore, the body needs strict regulations of the nutrients: an excess of nutrients will be quickly stored, and a nutrient shortage will be compensated for by releasing nutrients from the body stores into the blood.

Carbohydrates and sugars are stored in glycogen in the muscle and liver. Fat is mostly stored in adipose (fat) tissue, and some of it in the muscles and around the organs. Proteins can also be used as energy fuel, for which they first have to be converted to sugars (and urea). Protein is present in lots of different tissue, but its main storage location is in the muscles.

When the body needs energy (for example during exercise), it does not exclusively use one type of fuel, instead it will use different forms of fuel at the same time[1]. The situation determines how much of a fuel is used. For instance, when you have not eaten for more than 24 hours, your glycogen stores will be low. Your body will then switch to more fat oxidation (the burning of fat to get energy), and the breakdown of protein (and thus muscle) will be increased in order to supply the body with enough glucose. The latter is important, because the brain can only use glucose as energy fuel, and not fat. If there would be no glucose, the brain would stop functioning. When you have just eaten a big meal, your body will switch to predominantly carbohydrates, and will thus burn less fat or breakdown less muscle for protein.

During exercise, the intensity determines how much carbohydrates and fats will be burned. In general, when exercise intensity increases, carbohydrate oxidation increases[1,2]. Also, fat oxidation will increase when exercise intensity increases, but at some point it will decrease again. Therefore, there is an optimal intensity to burn fat. Implementing this knowledge in your (cardio) workout, could help with optimizing fat loss.

Fatmax
Studies tried to investigate which exercise intensity is ideal for fat loss. This optimal fat burning point, or the exercise intensity at which the maximal fat oxidation rate occurs, has been named Fatmax[3]. Exercise intensity in cardio can be expressed in Wmax: The maximal amount of Watt produced before hitting failure. Wmax is closely related to VO2max, which is the maximal volume of oxygen the body is able to use. Wmax and VO2max therefore reflect pulmonary (lung) and cardiac (heart) functioning. Wmax and VO2max are therefore higher in trained athletes. A Wmax of 100% means maximal intensity of (cardio) exercise. At that point, the body simply cannot work harder because it cannot use more oxygen than it already does.

One study tried to investigate the amount of fat oxidation during different exercise intensities[2]. The exercise intensities in cardio were expressed in Wmax. This study compared the amount of carbohydrates and fats that are burned during rest and at a Wmax of 40%, 55% and 75%. As can be seen in Figure 1, at Wmax 40%, the body will have a fat oxidation of about 50% (muscle and plasma TG + plasma FFA is about 25 KJ/min which is half of the total energy that is burned(50 KJ/min)). At a Wmax of 55%, fat oxidation is about 46% (30 KJ/min fat oxidation, 35 KJ/min glucose oxidation, total 65 kJ/min), so at this point in absolute numbers more fat is burned, but since glucose oxidation increases more, relatively less fat is burned. At a Wmax of 75%, fat oxidation is about 20% (20 KJ/min of total 80 KJ/min), which is both lower in absolute and relative numbers. Thus, exercising at 40% of max Watt has the highest relative fat oxidation.

Figure 1. Quantification of glucose and fat oxidation during different exercise intensities. Muscle glycogen and plasma glucose are part of glucose oxidation, muscle and plasma TG and plasma FFA are part of fat oxidation. %Wmax= percentage of the maximal exercise intensity displayed in Watt. Copied from van Loon et al (2001)[2].

This does not mean that exercising at a Wmax of 40% is best for fat loss. Once again, it depends on the situation:

When you have a lot of muscle mass and you are trying to lose some body fat to get to a low body fat percentage, it is important to minimize muscle loss. When the body is low on carbohydrates (during a cut), it will break down proteins and thus muscle mass to produce sugars. Loss of muscle muss is therefore minimized when fat oxidation is relatively high, and glucose oxidation relatively low. This is the case for a Wmax of 40%: less fat is burned than at a Wmax of 55%, but also much less glucose is burned. In this situation a Wmax of 40% might be ideal.

When you don’t have a lot of muscle mass, and/or when you just want to lose a lot of fat, minimizing muscle mass loss is less important than losing fat. In this case, a Wmax of 55% might be more ideal. In this situation, energy balance is much more important: you just have to burn more than you eat. Therefore, you might also exercise at an intensity of 75% Wmax. You burn less fat and much more glucose in this case, but this will indirectly result in greater fat loss because fat stores will be burned to supply the body with enough energy. However, when having little carbohydrates/glycogen in the system, exercising at a high intensity is very heavy, and it might therefore be a better option to exercise at an intensity of 55% Wmax.

According to literature, the optimal fat burning point could be different for persons, as gender, age, training status, diet and body composition might play a role[3]. An explanation for this could be that the bodies of trained athletes and people who consume low carb diets (either by fasting or high fat diets in the absence of carbs) are more efficient by being better able to switch to fat oxidation. Furthermore, there is some variation in Wmax, as these might differ per day. This variation is estimated to be around 3 to 7%[4]. It is therefore difficult to implement the Fatmax concept with 100% accuracy in your training strategy. It might be that you need a slightly higher or lower intensity than what is recommended to have optimal fat oxidation. However, it might still be a good approach for cutting.

How to implement Fatmax in your training
To start exercising at a certain intensity, you should know what your Wmax is. To determine Wmax, the following (simplified) protocol on a cycle ergometer could be used[4]:

Warm up for 5 minutes at 100W for males or 75W for females. Maintain at least 60 rotations per minute during the whole test.

Increase the intensity with 35W every 2 minutes, until exhaustion.

Exhaustion = the point at which you cannot maintain 60 rotations per minute for more than 20 seconds

Write down the maximal work load at exhaustion.

Now you know your Wmax, you can implement the concept of Fatmax into your cardio workout schedule to optimize fat loss.

Conclusion
The concept of Fatmax might be useful with regard to weight loss programs. The concept is however based on assumptions of physiology. I could not find any randomized controlled trials that investigated the validity of Fatmax for weight loss in comparison to another exercise regime. Therefore, it is not sure if optimal fat oxidation results in significantly greater weight loss compared to other fat burning strategies. I would therefore recommend to primarily stick to the key concept in weight loss, which is a negative energy balance. If you are able to implement Fatmax in your weight loss schedule, you might give it a try.

In short, Fatmax can be implemented in your training by:

Finding your Wmax with a cycling test.

Exercise at 40% of Wmax if you want to minimize muscle loss during a cut.

Exercise at 55% of Wmax if you want to maximize fat loss during a cut.

Look at your total exercise energy expenditure. A lower %Wmax also means that the exercise duration should be longer in order to burn the same amount of calories.

This is a very tasty dish. This pilaf recipe is from my grandmother, we usually eat it at our family gatherings. It’s a very easy recipe but it will get you a very divine meal!

Ingredients:

2 Chicken breasts

1 green bell pepper

1 red bell pepper

2 big onions

a box of champignons

1 can of peaches (1 L)

clove of garlic

Bell pepper powder

Curry powder

½ of a bottle of ketchup

ketjap

Recipe:

Cut the chicken breasts into cubes and chop the onion and the other vegetables.

Fry the chicken breasts and the onion together in a little olive oil. Add all the other ingredients except for the peaches. When everything is cooked and glazed with a nice saucy texture, add all of the canned peaches and a part of the juice. And you are all done! Ready to eat, serve it with a bit of delicious rice!

Probably everyone recognizes this situation: You have had a busy work week, waking up early at 7 am every morning, and going to bed at 11 pm. On Friday, you feel tired and you have the feeling that you should catch up on sleep, but you also want to go to bed later, since it’s weekend. Therefore, you decide not to set your alarm clock on Saturday and Sunday. You stay up late on Friday and Saturday, and you wake up at 11 am on Saturday and Sunday morning. Is this a good idea? Does sleeping in really help to catch up on sleep, rest and recover?

Sleep deprivation
As mentioned before in my other article on sleep and rest, there is not an optimal sleep duration that works for all people (if you missed the previous article, you can read it here: https://wageningenbeasts.com/2016/12/04/optimizing-your-sleep-and-biological-rhythm/). Some people need much sleep, others need less. The reason for this is differences in habit, but also differences in genetics (and of course differences in age, but this can be neglected since the readers of this article are probably all students). Therefore, no solid recommendations can be done on how long you should sleep.

If you get less sleep than you need, sleep deprivation (the need for sleep) will accumulate. Often when you have one bad night of sleep, you will still feel fine the next day, but when this happens for a few nights in a row you will start to notice the effects of sleep deprivation. Of course I don’t have to explain to you that (chronic) sleep deprivation is bad for you and can have serious health consequences. That is probably also the reason you want to sleep late during the weekends, to get some more rest. In theory, it is true that the body needs to catch up on sleep when it is sleep deprived, so in that respect you are right. There are however other factors that play a role.

The biological clock
Like mentioned before in my previous article, the biological clock is a mechanism that (a.o.) informs the body about time: the sensation of day and night. The biological clock is a complex system, because it can be influenced by many factors (think of light, psychological factors, activity, food intake). The complexity is also the reason why the biological clock does not adapt easily to changes in the daily routine. A jet-lag is a perfect example for this. After traveling it takes some time to adjust the sleep rhythm to the new time zone. However, it takes even longer before you are fully adapted to the new time (e.g. when you don’t need an alarm clock to wake up at a certain time). A rule of thumb is: don’t mess with your biological clock! It is best for the biological clock to have a regular pattern in sleep (most important), but also in things like food intake. Big changes in these patterns disturb the clock, which could result in sleeping problems, fatigue, changes in mood, concentration, study performance and metabolism, and in more severe cases (like chronic shift-work) in diseases like diabetes, cardiovascular disease and obesity, and even mortality[1-6]. A stable clock is therefore a healthy clock.

When you wake up early during the week and late in the weekend, this is confusing for the biological clock, especially when there is a great difference between the times of waking up. For each day you go to bed and wake up at a different time, the biological clock has to adapt. When sleeping in during the weekend and waking up early on Monday again, the biological clock keeps adapting back and forth. In this way, the body does not fully get used to waking up early during the week. This could possibly be the explanation why you are feeling tired during the week.

What I personally notice, is when I am not used to waking up early, and I wake up early even though I get my hours of sleep, I am still tired. This is because the biological clock is not used to waking up at a different hour, and not because the body did not get enough sleep. When sleeping in during the weekend, the body is not well-adapted to waking up early during the week, and this can cause the sensation of fatigue.

Conclusion
Thus, when you are tired after waking up early for a week, the likely cause of this is that your rhythm during the weekend is different, and not because you don’t get enough sleep. The latter is of course still a possibility, and in that case you could try to go to bed earlier to see if that helps. The answer to the question: ‘Is sleeping in during the weekend beneficial?’ is therefore: No, the benefits of some extra sleep do not outweigh the disadvantage of a disturbed biological clock. If you still want some extra sleep during the weekend, the best thing to do is to go to bed earlier.

Of course this is not a very attractive message. When it is Friday, we want to enjoy our weekend by staying up late and do fun things. This message discourages that. You might accept and implement this message by enjoying your weekend in the morning instead of late in the evening, but I can imagine that you don’t want to give up your nights out. Alternatively, when you go out partying, it might be better to still wake up early (maybe one hour later than on a weekday). In this way, you will have some sleep deprivation, but you can solve this by taking a power nap during the day or by going to sleep earlier in the evening. The upside of this, is that your biological rhythm will be more stable, which will be more beneficial in the long run.

Cut the sweet potato in 4 pieces and boil until soft. Cut the clove of garlic into small pieces and fry the gambas in the garlic with pepper. Add the spinach and the sweet potato into the pan with the gambas. Make sure the spinach shrinks and than add the curry paste with the coconut milk. Let this simmer for a bit and add the cherry tomatoes at the end!